by Tom Dominguez, Extension Service
If you’re in the process of any kind of construction, new or remodel, here are some things to think about in protecting the existing landscape and your soil.
With construction, terrible things happen to the soil. There may be a deceiving layer of beautiful soil showing, but what lurks beneath?
It’s truly a wonder anything ever grows after the manpower, equipment, mortar, mixed soil textures, chemical spills and other soil abusing practices are all over with. By some miracle, nature is resilient and plants usually do grow.
With any construction or remodel job — even a small patio or fence can cause some bad things that happen to good soil. Compaction from cement trucks, other heavy equipment, workers, dry mortar mix and cement debris are all bad for our desert, alkaline soils. All of these should be kept to a minimum so you can keep your peace of mind.
Protect your soil and landscape by agreeing about precautions with your contractor before any work begins. Identify driveways, service areas and alley ways as the primary traffic and work areas to help keep activity off the soil and plants. Tarps, sheets of cardboard or sheets of plastic can be laid down in areas where spills may occur.
While heavy equipment and manpower are essential to construction, they can be devastating to an existing landscape. For trees, 90 percent of their roots are in the top three feet of soil. One pass of a cement truck over the root system can crush the roots of a big, healthy tree.
The ideal thing to do is put up temporary fencing just outside the drip line of the tree to keep people and equipment off that vulnerable area.
Tree roots actually go beyond the drip line, but this will be a big help. Protect both your soil and tree roots by covering the traffic areas with a 6-inch layer of wood chip mulch or sheets of plywood. This may sound like a lot of trouble, but if you want a landscape that thrives, it will be worth it. Either of these materials helps distribute the weight over the area, reducing soil compaction and tree root damage.
Don’t allow materials to be stockpiled underneath trees either. The weight of the material can crush and damage roots as well as the equipment and manpower it takes to move these materials.
Temporary work sites are often set up under the shade of a tree, but for the sake of the tree relocate to a service area, drive or alley way.
With construction and remodeling there are often grade changes, trenching and digging that could damage trees and shrubs.
Grade changes of only a few inches can damage your plants. You can buildretainer walls and wells to protect a tree, if necessary.
Consider sand base hardscaping with brick or flagstone rather than
mortar. If trenching is necessary, consider trenching around the drip line. If that’s not an option, try trenching under the roots using air or water, which can minimize root damage.
Another way to protect the soil during projects is to avoid wet areas.
Wet soil is especially vulnerable to severe compaction when there’s any kind of movement and/or weight. Wet soil particles pack tightly together reducing the amount of air space between particles. Digging, trenching or any other wet soil disturbance damages the structure and condition of the soil, which can take years to restore.
Watch for neglected running hoses, wheelbarrows and other equipment washing out on landscape areas. Wheelbarrows and cement mixers shouldn’t be washed out on landscape sites because the lime in the mix causes harmful increases in the soil pH.
When landscaping projects are scheduled don’t allow tilling or heavy equipment for that project to take place if the soil is excessively wet.
While it may be easier to dig in wet soil, it seriously damages the soil structure.
Avoid excessively dry soil too. If the sprinkler system is down during construction, then you’ll need to hand water. Get out the ole sprinkler and hose and water enough to keep roots from desiccating.
Schedule watering when workers are gone for the weekend or holidays. Get the soil ready for a new or a repair with organic matter. Compost, leaves, grass clippings, cover crops and organic mulches will help restore the soil. If it’s an existing landscape, get back on track with a proper irrigation schedule.
Top dress everything with compost — even the lawn will benefit from an inch or two. All beds need a few inches of compost. After the compost is applied, beds will need a 3 to 4 inch layer of organic mulch. The organic matter will feed microorganisms and earthworms, which are essential for healthy soils and plants.
With a new landscape the soil is so damaged by construction and layering of various soil types that organic compost can be tilled into the soil followed by mulch. If you’re very concerned about soil improvement, use mulches that break down fast, like chipped and shredded leafy tree branches. If that’s not an option, try finely shredded pine bark mulch, landscaper’s mix and similar products.
Damaged trees will benefit from vertical mulching, which is a service some arborists provide. If not that, then mulch as much of the area under the drip line as possible. Water deeply on an as-needed basis in the drip line zone. Trim out dead wood as it occurs. With new or remodel construction consider rainwater harvesting. This is the time! With any luck at all, you and your landscape will live through the construction.
It’s not easy, but with preplanning precautions and lots of organic matter, things can be green.
Tom Dominguez is an agent with the Quay County Extension, NMSU Extension Service. He can be reached by emailing firstname.lastname@example.org or calling 461-0562.